strange one this one...
got a mate who has an 8v k-jet gti and he is having all sorts of problems with the running of it. Basically it starts ok from cold, but then starts to hesitate badly and misfire until its warmed up. then it runs ok. But after about 15 miles, you can hear the lift pump in the tank whining as if its pulling harder and as you slow down, the car starts to stutter and stammer until there is no acceleration at all and the car cuts out due to no fuel getting to engine. Strange thing is that if you stop the car and start it again, it starts again and all is well for the next 15 miles, then the same thing happens again. Its almost like a pressure has built up to a point where the car cant pump the fuel along the line anymore, and by switching the car off, it clears it, but i don't know. I would have said blockage in fuel lines, but as the fault clears after a restart, it sounds like something electrical. I do know that he has had a mess about with his idle and mixture/timing recently. It has had a new lift pump recently and new fuel filter.
Any clues as to what it is as he is avoiding driving his car at the moment. I say he should get to garage and get mixture and timing done first of all. anyone else had problems like this??